2006 Pontiac G6 GTP 3.9L LZ9 engine. Car has 185K miles and is a restored project car. The car drives smoothly and shifts (automatic 4speed) fine most of the time. It always downshifts smoothly and normally upshifts normally. However if the pedal is pushed down more than "normal" it has shifted "hard". The car shudders and it feels like the car was hit. Is the transmission going bad? What is the lifspan?
Is the transmission going bad?
Possibly.
What is the lifspan?
That depends on how the transmission been treated (driven aggressively?) and maintained (when is the last time the transmission was serviced?).
You would need a transmission expert with a professional-grade scan tool to diagnose what's going on. However at 18 years old and 185K miles the transmission is likely near end-of-life.
For future reference please use the title line for a short description of your topic, not the full text. Thank you. (Title edited.)
